1 Rheumatology Unit, Department of Clinical and Experimental Medicine, Azienda Ospedaliero Universitaria di Sassari, Viale San Pietro 8, 07100 Sassari, Italy. Electronic address: e.gianluca@libero.it.
2 Rheumatology Unit, Department of Clinical and Experimental Medicine, Azienda Ospedaliero Universitaria di Sassari, Viale San Pietro 8, 07100 Sassari, Italy.
3 Radiological Sciences Unit, Department of Clinical and Experimental Medicine, University of Sassari, Viale San Pietro, 07100 Sassari, Italy.